In 1921, by act of Congress, the site of Hot Springs's name was changed from the Hot Springs Reservation to the Hot Springs National Park. Growing to over 900 acres (3.6 km2), it included Hot Springs Mountain, North Mountain, West Mountain, Sugar-Loaf Mountain and Whittington Lake Park. It later was expanded to 5,000 acres (20 km2).
The springs are all grouped about the base of the Hot Springs Mountain, with a flow well over a half million gallons a day. The hot water is supplied to the various bathhouses with resulting income going to the U.S. Treasury. There are miles of roads and trails over the mountains. The park is open throughout the year.
The first bathhouses were really little more than brush huts and log cabins placed over excavations cut in the rocks to receive hot water that flowed from the springs. More elaborate bathing facilities soon developed, with wooden troughs delivering water from hillside springs to bathhouses along the east bank of Hot Springs Creek. Some of the tufa covering the hillside was excavated to accommodate the bathhouses. The narrow street along the west side of the creek was connected to the bathhouses by narrow bridges.
After direct federal supervision was exercised in 1877, major improvements were made. The creek was covered with stone arches, and above a street a hundred feet wide was built. All the squatters were evicted, rubbish cleaned, and a centralized plumbing system was begun. This was completed around 1890. In 1950 central cooling towers limited the maximum temperature to a safe level, so individual bathhouses no longer needed their own cooling systems.
The park operates a public campground at Gulpha Gorge, about two miles (3 km) from downtown Hot Springs.